electrolysis Flashcards

1
Q

what are positive electrodes made of?

A

graphite

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2
Q

what are negative electrodes made of?

A

graphite

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3
Q

why temp has to be high if aluminium oxide was used?

A

high melting points

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4
Q

how is operating temp kept low electrolyse

A

aluminium oxide is dissolved and mixed with cryolite

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5
Q

what type of reaction happened at negative electrodes

A

reduction

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6
Q

what type of reaction happen at positive electrodes

A

oxidation

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7
Q

two proxies of aluminium that makes it suitable?

A

low density and malleable

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8
Q

which side is positive and negative for electrodes

A

left os cathode right is anode

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9
Q

what is a cathode

A

negative electrode

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10
Q

what is an anode

A

postive electrode

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11
Q

what does cryolite do?

A

loweres the melting point

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12
Q

why is carbon monoxide poinisous

A

binds to hameogoblin limiting oxygen transportation

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13
Q

when is hydrogen gas produced

A

when metal is more reactive than hydrogen

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14
Q

when is a pure metal solid layer produced

A

when it is less reactive than hydrogen

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15
Q

(d) Magnesium oxide can be used to make magnesium sulfate by this reaction. MgO(s) + H2SO4(aq) - a student is provided with a beaker of dilute sulfric acid outline the steps she could take to obtain a pure sample of hydrated magnesium sulphate crysltrals using this reaction

A
mix two substances 
use excess of powder
filter 
heat to remove some water 
leave to crystallise
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16
Q

add damp blue litmus paper chlorine

A

turns red then bleches

17
Q

bubble chlorine into a solution of potassium iodine

A

black precipitate

18
Q

suggest why the volume of chlorine is less than expected

A

it is soluble in water

19
Q

why the phenolphatlin turns pink

A

it is alkaline so OH- is formed

20
Q

why is chlorine added to water

A

to sterilise the water

21
Q

what is meant by the term electrolysis

A

splitting by electricity

22
Q

suggest a suitable metal for inert electrodes

A

platinum

23
Q

what is electrolyte

A

a molten ionic compound that an electric current is passed through causing it to decompose

24
Q

what would you expect to see at the anode of inert electrons

A

bubbles of the negative ion

25
Q

what would you expect to see at the cathode of inert electrons

A

copper metal would coat the eletrode

26
Q

what happens if there no halide ions

A

oxygen and water are produced